Patching arrangement for carrier telegraph circuits



R. H. CLAPP Jan. 6,1931.

PATCHING ARRANGVEMENT FOR CARRIER TELEGRAPH CIRCJITS Filed March 5, 1930 VZNTOR ,BY CZLyv/a ATTORNEY Patented Jara, 1931 UNITED STATES PAH-:Nr OFFICE ROBERT H. CLAIIP, OF RAMSEY, NEW JERSEY, ASSIGNOR TO AMERICAN TEL:EPIHONE` AND TIIEJIJEIGRAIIE COMPANY, A CORPORATION OF NEW YORK PATCHING ARRANGEMET FOR CARRIER TELEGRAPH CIRCUITS Application filed March 3, 1930. Serial No. 432,848.

This invention relates to carrier telegraph circuits, and more particularly to four-wire carrier telegraph clrcuitsv in which signalsV *aref/sent in one direct-ion over one pair of wires and in the opposite direction over another pair of wires. 4

In such a four-wire arrangement the twoway circuitis dependent upon four wires, of course,.as distinguished from the arrangement in which .the two-way service is obtained bythe useofdifferent frequencies on a single pair of wires, and a. subscriber sending on one of the two airs of the four-wire circuit is not aware o trouble on that pair untilhe is advised of it from the receiving end. Accordingly, it becomes of particular importance in the case of four-wire operation that the hazard of interruption to the servicebe reduced. 29 The principal object of this invention is to provide for the automatic substitution of a one-way -transmission'path for that which In general, the applicant accomplishes this and means responslve to a failure of anyone of a plurality of paths for substituting the sparev path for the failed path by effecting r the necessary disconnection and connection 30 at the receiving and sending ends of the circuit.

The various features and advantages of th'einvention will be understood whenlthe following detailed description of fone desirable embodiment thereof is read with refervence to the accompanyingdrawing, which shows in diagrammatic form that embodiment andthe circuits affected by the opera.-

tion thereof. 40 With reference to the details of the drawing, a station 'A at the left lis shown connected to station B at the rightby two four-wire circuits. The circuit shown in the upper' v part of the drawing ycomprises a two-wire 4,5 line L1 adapated for transmission from A to B, and a second two-wire lineL2 `adapted for transmission from B to A. Likewise, the

' Qlower four-wirecircuit includes line L1 for transmission from A to B, and line 'L2' for transmission from to A. At each end of- `tail the apparatus and circuits-which, in acfrom :the time,

object by providlng a spare one-way path vthe lock-up relay, and a relay each four-wirecircuit there are shown telegraph sending apparatus and receiving r'e-'Q lays represented by s and 7", respectively.

It is proposed to show and discuss in decordance with the invention, serve to patch 1n a Spne line SL, adapted for transmission to A, upon the failure of either of the two-wire lines L2 and L2. It will be understood, of course, that provision is made for substitution in the case of a failure of4 line Lll or line L1 by the duplication of the equipment shown in detail.

' Sincethespare path SL, for instance, will presumably be in use as a substitute for one of the lines L2 and L2 only a small part of this spare path can be used during the greater part ofthe time for service -mes sages or what may -be termed order Wire business, for instance. Accordingly, this `spare line SL is shown normally connected to' aservice message sender at station B and a. service message receiver at station A, this apparatus `being indicated schematically.

The apparatus employed primarily for the substitution of the spare line SL for the line L2 of the upper four-wire circuit, will rst be considered. Connected between the armature and the spacing contact (not specically shown) of each of the receiving relays of the upper circuit at station A, is a.

slow release relay R; Associated with these slow release relays are relay R1, whichfmay be f termed the switching relay and has as its particular function the switching of the receiver connect-ions from line L2 to thespare' line SL, relay R2,which may be termed the lock-out relay, relayRs, which ma be termed R, whichv functions directly in response'to a failure of either line L2 or lineL2. to disconnect the service message receiver from line SL and aid in the connection thereto of the telegraph receiving relays. In addition, there aregprovided at station A in particular association with the upper circuit an electro-magnet AR, which may control/ an-,alarm, a'lamp S, an oscillator O and a.-'ack J`."-' The functions off" these elements will be considered in detail hereinafter. Itiis to be noted that relay R, 10c

is arranged to operate two armatures controlling the connections to the two wires of line f L2. Likewise, it is to be noted that relay.RR has two armatures controllingI the connections to line SL, and that this relay has two windings, one associated with the upper four-.wire circuit and `the 'otherA associated with the lower vfour-wire circuit. It will also be noted that the various elements directl `associated with the u per circuit have, wit (the exception of relayIRR, corresponding elements similarly designated but primed, directly associated with the lower four-wire circuit. 'Y f If all the receiving relays 7' of the upper circuit at station A remain open long enough in response to a failure of line L2 to ermit the release .of the slow release relays the armatures and back contacts of these relays R are connected in series to form a path from battery, as indicated, to ground through the back contact and right-hand armature of relay R2 directly associated with the lower four-wire circuit, the back contact and aimature of relay R2, the left hand winding of relay RR, jack J, the winding of relzllgl R2 and the windings of relay R2.A Relay 1, as indicated above, operates to throw its armatures out of contact with the wires: of line L2 land into contactwith the leads Z1' and Z2. Relay R2, by the operation of its ri ht-hand e armature, breaks a circuit which inc udes the switching relay R1 associated with the lower 1' four-wire circuit and accordingly prevents the substituting operations in connection with the lower circuit. The operation of the left-hand v armature of relay R2 removes groundnormally connected through the back contact of.- the armature from the special oscillator O, and it will be noted that battery is .connected :to this oscillator and to the winding of relay AR through lthe armatures and back contacts of the slow release relays R. Through the closed contact of the left-handarmature `of relay R2 ground is connected to a circuit including` a battery, the lamp S and the windingof relay R3. The operatlonof relay R3 disconnects the slow release relays R `from the relays of the chain now under discussion and applies battery to replace that supplied through the contactsl of relays R to old the switching relay R1 and the relay RR operated until a` disconnection by manual operation of the jack J. It

will be understood that it is desirable that relay R2 should be somewhat sluggish in re-l leasln in order that time may be allowed for the suitable function of relay R3. Relay RR y responds to the release of the. slow release mi.WRI*andthetelegraph receiving relays r. ,65

relays R to throw its armatures out of connection with the serviceme'ssa e receiver and into connection with the leads 1'and Z2, which form connections to the armatures of relay Win `be From the discussiondgiven above it understood that the failure ofthe two-wire line L2 results, if the spare line SL is not in l substitute use, in the transfer of the connections of the lineSL from the service message apparatus-to the receiving relays r and failure of line L2 follow immediately upon I that of line L2. In addition, relays R1, R2, Rs and RR are locked up and can be released only by the manual operation of the'jack J The alarm control electromagnet AR, it will be noted, is designed to operate as long as all theA receiving relays 1" are open. In response to vthe release of relays Rand the removal of ground through the operation of'relay R2, current is sent out from the special oscillator Ol on the line L1 to station Since this` special switching currentiis transmitted in'- frequently and only for brief periods, it may be quite unusual in magnitude and frequency. At station B a -ilter functions to select the special switching current, which is Aamplified and rectified to operate the relay SR.' Thisrelay operation connects battery to a circuit including the"windings ofrelays RRI, RR2 and RR', a lampS1 and a jackJl. These elements, with the ex'ception of relay RR', are particularly associated withthe upper fourwire circuit and have corresponding elee ments, similarly designated but primed, in association with the lower four-wire circuit. The relay RR', it will be noted, has, like the relay RR at station A, a winding in connection with each of the four-wire circuits. Re-

lay RR2 corresponds to relay ,R1 at the other station vand functions to disconnect the telel cation is established-.over line SL, thel slow release relays R are pulled up; thus battery supply `is removed from the alarm relay yAR and the oscillator O. Since the special switching current is transmitted from A to B only when the lock-out relay R2 at A is closed and the receiving circuitsa't'A areopen, no lock- Y out relay is-necessary in connection with the telegraph. sending apparatus at ,station B because R2 cannot be closed ifthe line SL is already in use.

Thus,'in response to a vfailure of the twowire channel L2, we .have the substitution of the spare two-wireline SLfor line L2 andthe incidental disconnection from the line SL of the service message apparatus at both station A and station B, together with suitable alarm indications. Furthermore, we have Vprotection against the substitution of line SL for line-L2 while the former is in use as a substitute for line L2. When the regular line L2 has been repaired, the normal conditions of the system may be restored by the simple operation of opening the 'circuits at the jack J of station A and the .jack J1 of station B. This jack operation, which is preferably performed simultaneously at the two stations, removes battery from the windings of the relays and causes the relays to open.

It'will be understood that if the line L2 fails, slow release relays'R associated with the telegraph receiving relays r of the lower circuit at station A release and cause the operation of relay RR, R1', R2 and Rs; in addition, the electromagnet AR', the lamp S and the special oscillator O are operated. Accordingly, the spare line, unless it is already-.in use as a substitute for line L2, is substituted for line L2', at the service message equipment is disconnected and special switching'cu'rrent is sent over line L1 to station B to operate relays SR', RR,`RR1 and RR3 to perform the necessary switching and lockup operations at that station. If the spare line is already in use, ready, thus preventing the operation ot R2 and the picking up of the spare line. If no spare line is available, the operation of relay AR will sound an alarm.

It is tobe understood that the spare line SL may be'made to serve as substitute for a greater number of one-way channels than the two specificially sliown'by the simple modification of providing more lock-out relays.

It will be understood further thatfthe fourwire system shown is equipped at stations B and A, respectively, with apparatus associated with the telegraph receiving relays at B and the telegraph sending 4relays at A to take care of the substitution'of a spare line SL adapted forV transmission from A to B upon the failure of line L1 or L1. The apparatus and the 'circuits involved are identical with those shown and described in detail in connection with the substitution of line SL for L2 or L2', and no further detailed description is deemed necessary herein.v

While the invention has been disclosed in one specific embodiment which is deemed desirable, it will be understood that it is cap-l able of embodiment -in other and different forms within the scope of the appended claims.

'What is claimed is: 1. In a carrier telegraph system, a plurality of regular one-way paths, receiving ap- "paratusviat one'end of each of said paths and sending apparatus at the other end thereof,

a spare one-way path, and means responsive R2 will be operated alvity 'of four-wire circuits each including two regular paths adapted for transmission in v opposite directions, 'sending apparatus and Y to the failure of anyI one ot said regular paths for disconnecting the receiving apparatusand the sending apparatus from the respective ends ofthe failed regular path` and connecting the same to said spare path.

2. In a carrier telegraph system, a plural- K ity of regular one-way paths, receiving apparatus atone end of each of said paths and sending apparatus at the other end thereof, a spare one-way path, service message transmission apparatus normally connected-to said spare path, and means responsive to the failure of any one of said regular paths for disconnecting the receiving apparatus and the sending apparatus from the respective ends 'of the failed regular path, disconnecting said service message transmission apparatus from said spare path and connecting said receiving and sending apparatus to said spare path.

3. In a carrier telegraph system,'a plurality of four-wire circuits each including two regular paths adapted for transmission in opposite direction-s, sending apparatus and rece1ving apparatus at each end of each ofI said four-wire clrcuits in appropriate connection with said paths, a spare path, and means responsive to the failure of any given one of said regular paths for disconnecting the sending and receiving apparatus from said path and connecting the same to said spare-path.

4. In a carrier telegraph system, a pluralsending apparatus and the receiving apparatus from said regular path, disconnecting said service message transmission apparatus from saidspare path and connecting the sending apparatus and the receiving apparatus to said spare path.

5. In a carrier telegraph system, a plurality of four-wire circuits eachvincluding two regular paths adapted for transmission in opposite directions, sending apparatus. and

receiving apparatus at each end of each of said four-wire circuits in appropriate connection with said paths, a spare path, means associated with the receiving apparatus and responsive to the operative failure of the regular path connected therewith for disconnecting said apparatus from said regular path `and Iconnectimg the same to said spare path,

and meansat the sending end of said regular path responsive to operations at thereceiving end thereof for disconnecting the sending apparatus from said `regular path and connecting the same to' said spare path. r

6. Inv a carrier telegraph system, a pluralimpulses for-disconnecting t e sending apity of .four-wire circuits each including two c regular paths adapted for transmission in opposite d1rections, sendingy apparatus and r e ceiving apparatus at each end of each of said [four-wire circuits in appropriate-connection with said paths, and the following elements associated with each group of regular paths l adapted for transmission in a common direction: aspare path, means at the receiving end responsive to the failure of any one of sald regular paths for disconnecting the receiving apparatus from said regular path and connecting the same to said spare path, means at the receiving end responsive to said failure for sending speclal impulses to the sendlng end, meansat the sending end responsive to said impulses for disconnecting'the sending apparatus from said regular path and con- "nectin'g the same to said spare path, and

means forpreventing the operation of said d1sconnect1ng and connectmg means to substitute said spare path for more than one ofA y rection: a spare pathfservice message transsaid regular'paths at a time. I

7. In a carrier telegraph system, a plurality of four-wire circuits each including two regular paths adapted for transmission in opposite directions, sending apparatus and receiving' apparatus at each end of each` of saidfour-wire circuits in appropriate connection with said paths,and the-,following elements associated with each group of regular paths adapted for transmission in a common -dimission apparatus normally connected to said l, spare path, means at the receivin end re- .sponsive to the failure of any one o said reg- `ular paths for disconnecting the receiving y apparatus from said regular path, disconnecting the ser-vice message transmission apparatus at the receiving end from" said spare path and connecting the receiving apparatus to said spare path, means at the re'- ceivi'ng end responsive to said failure for @sending special impulses to the sending end,

nov

.' time. i

In testimony whereof, I' have signed my means atl the-sending end res onsive to said paratus from said regular path, disconnect- .lng the service message transmission apparatus at the sending end from saidspare path and connectingthe sending apparatus to` said spare ath, and means'for preventing the operation of said disconnecting and connecting means to substitute said spare path for more than one of said regular paths ata name to this'speciication this'28pth day of February,"l930. 1 f ROBERT H. CLAPP. 

